In the past few decades, water-based amusement rides have become increasingly popular. Such rides can provide similar thrills to roller-coaster rides, with the additional features of the cooling effect of water and the excitement of being splashed.
The most common water-based amusement rides are flume-style waterslides in which a participant slides along a channel or “flume”, either on his or her body, or on or in a vehicle. Water is provided in the flume to provide lubrication between the body/vehicle and the flume surface, and to provide the above-mentioned cooling and splashing effects. Typically, the motion of the participant in the flume is controlled predominantly by the contours of the flume (hills, valleys, turns, drops, etc.) in combination with gravity.
As thrill expectations of participants have increased, demand for greater control of participants' movement in the flume has correspondingly increased. Thus various techniques have been applied to accelerate or decelerate participants by means other than gravity. For example, a participant may be accelerated or decelerated using powerful water jets. Other rides use a conveyor belt to convey a participant to the top of a hill the participant would not otherwise crest on the basis of his or her momentum alone. For safety reasons, such techniques are generally used only on waterslides where the participant slides along the flume in a vehicle.
However, such existing means of controlling the movement of a participant can raise safety and comfort concerns even when he or she is riding in a vehicle. For example, a water jet powerful enough to affect the motion of a waterslide vehicle could injure the participant if he or she is hit in the face or back of the head by the jet, as might be the case if the participant falls out of the vehicle. Similarly, a participant extending a limb out of a vehicle could be injured by a fast-moving conveyor belt.